Skin cancer and related growths both on the skin and on other living tissue are relatively common maladies apparently occurring with increasing frequency partially due to depletion of ozone in the upper atmosphere. Such growths are sometimes characterized by finger-like extensions or striations therefrom. Early detection and removal of these growths in their entirety can avoid the much more complicated and sometimes fatal consequences of delayed or insufficient treatment. It is especially important to remove cancerous growths before such growths metastasize to other parts of the body.
Surgical excision is the first method usually considered for removal of skin neoplasms as such an approach has historically proven most advantageous for removal of small tumors. Surgical excision has the disadvantage of allowing a significant number of recurrences because of the clinically hard to see or invisible finger-like extensions of tumorous growth which may extend beneath otherwise healthy appearing skin beyond the area being treated during the excision. Further, tumors which occur in areas where it would be difficult to obtain closure are not generally considered for simple excision.
A second technique previously used, known as Mohs' Technique, involves performing layered excisions which are fixed and carefully examining each layer for any cancerous growth to ensure no cancerous tissue remains. A variation of this is the fresh tissue variation of the Mohs' technique in which sequential horizontal sections are removed from the surface one at a time and microscopically studied until no cancerous material is found. In this manner the tumor is traced to its farthest and deepest extent which does allow for removal of all of the finger-like extensions which might otherwise escape detection using conventional surgical techniques. Unfortunately, substantial amounts of healthy tissue are unavoidably simultaneously surgically removed using this technique. Also, the use of the Mohs' technique can be costly and very labor intensive as each section must be prepared and tested before the next section is taken while the patient waits.
A third technique is electrodessication and curettage (ED & C). The skin is curetted with a large and a small curette in an attempt to uncover all extensions of the tumor. The affected skin is then superficially dried and charred using a monopolar probe having a source of moderately high voltage, low amperage alternating current. The drying and charring cycle is then repeated two more times, with the resulting wound left to heal by secondary intention. The electrodessication and curettage technique has two major problems: one being the relatively high rate of recurrence, and the other being the cosmetic defect normally remaining after the wound has healed.
Cryosurgery is another relatively simple technique for ablation of epitheliomas. Often, the physician curettes the tumor prior to the cryotherapy. Generally the affected tissue is frozen to -60.degree. C. in an ice ball. After two freeze-thaw cycles, the wound is allowed to heal. Cryosurgery may generally leave hypertrophic scars and can cause excessive tissue destruction and scar formation with concurrent deformity of adjacent otherwise healthy tissue. Other problems encountered with cryosurgery include pain, significant cutaneous necrosis, risk of infection, and local neuropathy.
Radiation therapy has also been used to treat such cancerous growths. Radiation therapy has two primary drawbacks. The first is the secondary injury that often follows the use of radiation; the second is the extremely high investment cost of the equipment needed for radiation therapy.
The use of a pressurized narrow jet of fluid as a means of removing softer tissue without damage to adjacent healthy tissue provides the ability to remove only the diseased tissue leaving the healthy tissue viable and the resulting wound relatively easy for the body to repair with relatively little disfigurement or secondary damage to surrounding tissue. The pressure source for the jet is adjusted such that the energy released at impact of the liquid of the jet with the affected tissue is sufficient to allow the jet to penetrate not only the main tumor mass, but also into the long, yet narrow and initially clinically invisible, tendrils of growth which radiate outward from the main tumor, thereby allowing the removal of the diseased tissue without damage to the adjacent healthy tissue.